[amsat-bb] HELIX REFLECTOR?

[Pete Norris, K1HZU]

Hi All:
I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more manageable size than I had before. The only reference to reflector size I can find is, "minimum 20" ". I may be looking in the wrong places. I would appreciate it, if someone would steer me in the right direction.
Thanks,
Pete, K1HZU